Engine cooling apparatus



Feb. 28, 1950 T. J. BAY 2,498,637

ENGINE COOLING APPARATUS Original Filed 001,. 31, 1945 3 Sheets-Sheet 1WATER HEAT EXGH.

ENGINE G 2 THOMAS J. BAY

Feb. 28, 1950 T. J. BAY 2,498,637

ENGINE COOLING APPARATUS Original Filed Oct. 31, 1945 .3 Sheets-Sheet 2IIIUI THOMAS J.'BAY

Feb; 28, 1950 T. J. BAY 2,498,637

ENGINE COOLING APPARATUS Original Filed Oct. :51, 1945 3 Sheet s-Sheet 3gwuzwvbob 4 THOMAS J. BAY

Sam/wan Patented Feb. 28, 1950 ENGINE COOLING APPARATUS Thomas .7. Bay,United States Navy Original application October 31, 1945, Serial No.

625,928. Divided and this application September 22, 1947, Serial No.775,512

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) 2 Claims.

This application is a division of my application Serial No.625,928,.filed October 31, 1945, for Engine cooling system andapparatus, now Patent No. 2,446,995, dated August 17, 1948.

This invention relates to cooling systems for internal combustionengines and to apparatus for use in such systems, and particularly tosystems of the type disclosed in my Patent No. 2,365,166 grantedDecember 19, 1944. The principal objects of the present invention are toprovide apparatus for use in systems like those disclosed. in thatpatent and in this specification, and also to provide a system improvedin certain respects over the earlier one.

The system disclosed in Patent No. 2,365,166 constituted improvementsin. internal combustion engine cooling wherein. the engine cooling waterafter having passed in heat exchange relation with a prime coolingmedium is then passed in heat exchange relation with the lubricating oilor a portion of the same. Among the objects of that invention wereprovision of means for controlling, the cooling water temperature andfor controlling the temperature of the lubricating oil. One desirablepossibility in such a system is to provide for. the rapid elevation oftemperature of both the water and the lubricating oil on starting thecold engine. This serves to minimize engine wear. renderthe installationmore reliable in service and reduce expense of maintenance.

While the system provided in the above mentioned prior patent has givengood service and in many applications is very satisfactory, I have inthe present instance devised an improvement on that system particularlyvaluable to provide for bringing the lubricating oil toproper operatingtemperature as rapidly as possible after starting a cold engine andto'prov-id'e for close control of lubricating oil temperature incases'w'here the engine design provides for relatively large rise inlubricating oil temperature during its circulation through the engine. Ihave further devised improved apparatus for use in the new system aswell as in the system previously disclosed.

With the object of clearly disclosing the invention, the accompanyingdrawings will be discussed in connection with the description aspresenting preferred embodiments from which numerous departures may bemadewithin the scope of the invention.

Figure 1 is a representation of a complete systemfor controlling thetemperatures of water and of lubricating oil for an internal combustionengine.

Figure 2 shows a heat exchanger with a preferred form of thermostaticvalve incorporated in its structure.

Figure 3 shows a heat exchanger with a modifled form of valve.

Figure 4 shows a further form of heat exchanger involving sectionalstructure and a plus rality of valves.

In Figure 1 the major elements of the engine cooling system comprise theinternal combustion engine I, water heat exchanger 2 and oil heatexchanger 3. The engine heat exchange medium leaves the water jacket bypipe 4 and returns through pipe 5. The entire flow or any portion of thecirculating lubricating oil is taken from any suitable point in thelubricating system at B and returned at 'l.

Both heat exchangers are represented as being of the type in which twofluids are passed in heat exchange relation with each other but withoutmixture of the two fluids. In order to convey this idea the two fluidsare shown as passing through separate coils within the exchangers. Thusin exchanger 2 the primary cooling medium passes through coil 8, and theengine jacket water through coil 9, and in the oil heat exchanger 3water passes through coil it while the lubricating oil flows in coil II.

The various elements of the piping represented for conveying the severalfluids involve a section E3 to the water heat exchanger, a section !4between the two heat exchangers, a portion l5 from valve ll to valve l9,and a section l6 constituting a by-pass around the oil heat exchanger topipe 5. Valves ii and H) are thermostatically controlled valveshereinafter fully described. In the case of valve l! the control elementI8 is in thermal relationship with the water leaving the engine, whilethe thermostatic element 20 of valve 19, though the valve controls watercirculation, is in thermal relation with, and controlled by thetemperature of, the oil leaving heat exchanger 3.

Figure 1 is diagrammatic in nature and does not, save in a generalmanner, indicate the construction of the various elements.

While it appears that external pipes and valves are employed, this isnot necessarily true, as will appear later from description of my newlydevised heat exchanger. The description will proceed by setting forththe system as applied to a marine engine installation wherein sea waterconstitutes the prime heat exchanger medium flowing in coil 6, but it isto be noted that the heat exchanger 2 might be of any type capable ofcooling the fluid passing in coil 9. Since the present system ismodified particularly for improved performance in connection withrapidly bringing the engine to an eflicient operating temperature, thisoperation will be first described and is as follows:

On starting of the engine, cold water under the influence of the enginewater pump flows in the direction of the arrows at pipes 4- and 5. Thewater is forced to now through pipe l5 since the valve I1 is closed toflow therethrough by operation of its thermostatic element I8. Forpurposes of this diagrammatic presentation, valve I1 is indicated as ofa type allowing flow in one or both of two directions, flow beingallowed through I3 and I5 when the water at I8 has reached apredetermined elevated temperature and through I5 only at lowertemperatures. Valve I9 is of the type which I have in my previous patentspecification described as a threeway valve. Its operation is to directfluid flow in one or the other of two directions in this case to pipes2| or I6 depending upon the temperature of the oil affecting the element2|]. When the thermostat is at a low temperature, action of valve I9 isto send all the water through pipe 2| and thus through coil III of heatexchanger 3. Therefore, under starting conditions the course of theengine jacket water will be in sequence through pipes 4, I5, valve I9,pipe 2|, coil II] and pipe 5 back to the engine jacket. The water heatexchanger 2 is completely bypassed, as is evident, and thus the enginewater, subject only to a minimum amount of heat radiation, will have itstemperature raised rapid- 1y by the heat supplied by the engine. Furtherall the engine water flows through heat exchanger 3. Since inpractically all internal combustion engines a great deal more heatpasses into the cooling water than passes into the lubricating oil, itwill be seen that the heat exchange relationship between the rapidlyheating water and the oil in exchanger 3 will serve to increase thetemperature of the cold oil rapidly, which is one of the main objects ofthe system. When the oil is at proper operating temperature, valve I9will act to control the amount of water passing through II] from theengine. When full operating conditions have been reached all the cooledwater from heat exchanger 2 will pass through heat exchanger 3, whilepart of the water will by-pass both heat exchangers and return to theengine. In case the oil is cooled to too low a temperature, valve I9will open partially, allowing some of the hot water from valve I1 topass by, pipe 2| to the oil heat exchanger 3. In this manner a veryclose control of the lubricating oil temperature is possible. This is ofespecial benefit in connection with engines using a small quantity ofoil which may have to absorb a great deal of heat at high poweroperation of the engine.

Figure 2 indicates a heat exchanger containing the essential elementsfor constituting the water heat exchanger 2 shown in the diagram ofFigure 1. This heat exchanger comprises a cylindrical shell 25, waterchests 26 and 21 at either end of the shell and a tube assemblycomprising headers or tube sheets and 3| and tubes 32. Inlet 28 andoutlet 29 are provided for the fluid which will flow exteriorly of thetubes 30 and 3|, in the case here described, said fluid being sea water.In addition to the heat exchanger tubes, there is provided a by-passtube 33 also secured in the tube sheets 39 and 3|. Water inlet 34 isprovided in the water chest 26 and an outlet 35 in water chest 21. As anintegral portion of the inlet 34, there is an extension constituting avalve body 31 having openings in its sides. A valve closure 38, operatedby a thermostatic element 39, serves to control flow through theopenings 40 and, indirectly, through the by-pass tube 33. As will beapparent from the drawing, valve closure 38, when in its extendedposition, will uncover openings 40. When in its retracted position theclosure 38 will cut off communication from the inlet 34 to the waterchest 26. At intermediate positions the water flow will be divided.Communication from inlet 34 through tube 33 is allowed at all times.Thermostat element 39 is assumed to expand when the incoming water ishot and contract when it is cold, it being contemplated that suitableadjustments may be provided in known manner. The element may be of anyof the bellows, bimetallic or other type.

As applied in the system according to Figure l, the space within theshell 25 corresponds to coil '8. The assembly of tubes 32 corresponds tocoil 9, the thermostat valve to valve I1, tube 33 to by-pass pipe I5,and element 39 to element I8.

In operation sea water will circulate through the shell around thetubes. Upon starting the engine, cold water from the engine will enterinlet 34, from pipe 4 of Figure 1, and pass directly through valvehousing 31, valve 38, and by-pass tube 33, the downstream end of whichis connected to tube I5 of Figure 1. Since the water is cold, thermostat39 is contracted and ports 40 in valve housing 31 are closed by valve 38so all the water coming from the engine must pass into tube I5 of Figure1 which conveys it to three-way thermostatic valve I9 of Figure 1. Sincethe lubricating oil circulating through tube 1 from the oil heatexchanger 3 is also cold when the engine is started, the thermostat bulb23 in thermal contact with the cold oil in pipe I causes three-way valveI9 to divert the entire quantity of water entering it from tube I5 totube 2|, allowing none of it to pass into tube I6. Thus the flow ofjacket water when the cold engine is first started is as follows:through pipe 4 to valve 38, to by-pass tube 33, to tube I5, throughvalve I9 to pipe 2| through the jacket water circuit of the oil heatexchanger 3, and back to the engine through tube 5.

Since the cooling tubesof the water heat exchanger are being by-passed,the heat absorbed by the jacket water in the engine is not beingdissipated and the jacket water rapidly increases toward the desiredoperating range. When it reaches the desired temperature the thermostat39 extends, gradually opening ports 49 in valve housing 31 andpermitting sufiicient jacket water flow through the cooling tubes 32 forcooling as necessary to maintain a constant temperature of the jacketwater passing from the engine through tube 4. This cooled water isdischarged from tubes 32 into water chest 21, and thence out of thewater heat exchanger through outlet 35 and into tube I4 of Figure 1.

It will be noted that jacket water is not admitted to cooling tubes 32until its temperature leaving the engine has been elevated to operatingrange. Prior to this time, all the heat absorbed by the jacket waterflowing through the engine is available for heating the lubricating oilin oil heat exchanger 3. In this way the lubricating oil is rapidlyheated to the desired operating range. When the lubricating oilapproaches the pipe 2|, cooled jacket water from the jacket water heatexchanger is flowing through pipe 14 into which tube 21 discharges, andunder this intermediate condition a mixture of hot and cooled jacketwater flows into the oil heat exchanger.

We may now consider the conditions obtaining when the engine has beenoperating for some time and temperature conditions have stabilized.Valve I1 is now dividing the flow of jacket water so as to maintain aconstant temperature of the jacket water leaving the engine. Valve 19 isdividing the flow of hot jacket water, entering it from tube 15, betweentubes 2| and I6. Just suflicient flow of hot water is permitted throughtube 2| to dilute the cooled water coming from the water heat exchangeras necessary to keep the lubricating oil, flowing to the engine from theoil heat exchanger through pipe I, at the desired operating temperature.The balance of the hot jacket water flowing into valve I9 from tube [5passes through tube It and combines with the jacket water issuing fromthe oil heat exchanger in pipe 5. Thus, by proper initial adjustment ofthermostatic valves I! and [9, the temperature of the jacket waterleaving the engine and the temperature of the lubricating oil enteringthe engine are both automatically maintained within the desiredoperating range, and at the same time the temperature of the jacketwater entering the engine can be reheated to a temprature approaching oreven higher than the temperature of the lubricating oil entering theengine.

Figure 3 illustrates a heat exchanger and valv of a modified design. Allparts are similar to those in Figure 2 and identical referencecharacters are used, except for the valve closure which is referred toas 48 since it is different from the valve closure 38. The action ofthis valve is somewhat different from that of Figure 2 in that positivecut-off occurs in both positions. This form of valve is capable ofclosing communication with by-pass tube 33. In operation of this device,cold water entering inlet 34 will pass through openings 49 and by-pass33. When the water has warmed sufliciently action of the element 39 willuncover openings 40 allowing an increasing portion of the water to passthrough tubes 32, water chest 21, and outlet 35. When the valve isentirely extended, no water is by-passed by reason of the seating of thespherical face 55 on seat 56. A further difference is that by-pass 33discharges into water chest 21, rather than having a separate outlet.

Figure 4 represents a modified type of heat exchanger for use eitherwith an oil or water system, and comprising a plurality of thermostatcontrolled valves. Reference characters are applied to the same elementsinvolved in the construction of Figure 3. Major differences involvedcomprise dividing the tube assemblies by providinga plurality of by-passtubes 33 with their associated thermostat valves. Action of the valveswill be identical with that heretofore described. Provision of theplurality of valves entails a number of advantages, prominent amongwhich are use of standard sizes of valves for various sizes of heatexchanger, and possibility of satisfactory operation, even though one ormore of the valves should fail. It is contemplated that the valves willbe so constructed that upon failure they will act to open communicationwith the tubes 32 in order to utilize the full heat exchange capacity ofthe system. The valves may be of the type shown in Figure 2.

In the heat exchangers described above, the bypass is as shown in orderto secure the advantages of integral construction of the valve.Negligible heat exchange will occur due to the relatively small surfacesexposed.

It is believed that advantages not specifically referred to will beobvious, as will modifications not departing from the scope of theappended claims.

The invention described herein may be made and used by or for theGovernment of the United States for governmental purposes without thepayment to me of any royalties thereon or therefor.

What I claim is:

1. In a heat exchanger for liquid cooling apparatus, a chamber, inletand outlet headers within said chamber, heat exchange tubes secured toand between the headers, a plurality of by-pass tubes positioned betweenthe headers, tubular valve housings having ports therein secured withinthe inlet header to the inlet end of each of said bypass tubes, a valvein each inlet housing operative to open and close said housing ports andthe connected loy-pass tube in succession, heat responsive means forholding each of said valves in position to close said housing ports andopen said connected by-pass tubes when unheated but operative whenheated to actuate said valves to open said ports and close said by-passtubes and an inlet pipe connected in series to each of said inlethousing and heat responsive means whereb said valves are actuated insuccession on change of temperature in liquid supplied to the inlet endof said inlet pipe.

2. In a heat exchanger for liquid cooling apparatus, a chamber, inletand outlet headers within said chamber, heat exchange tubes secured toand between the headers, a plurality of by-pass tubes positioned betweenthe headers, valve housings having wall ports therein secured withinsaid inlet header to the inlet end of each of said bypass tubes, a valvein each inlet housing operative to open and close said housing ports andthe connected by-pass tube in succession, a thermosensitive deviceoperatively connected to each of said valves to. close said ports andopen said by-pass tubes when unheated, and to open said ports and closesaid by-pass tubes when heated, and an inlet pipe connected in series toeach of said inlet housings and thermosensitive devices, the sections ofpipe between successively connected valve housings from the inlet pipeend being of progressively smaller diameter.

THOMAS J. BAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS lumber Name Date 1,228,765 Fekete June 5, 19171,311,809 Giesler July 29, 1919 1,324,865 White Dec. 16, 1919 1,330,342Prell Feb. 10, 1920 1,543,342 Porsche June 23, 1925 1,578,805 CooperMar. 30, 1926 2,191,627 Schutt Feb. 27, 1940 2,291,637 Kohlmann Aug. 4,1942 2,353,577 Magrum July 11, 1944

